如何让 AtomicInteger 在 Runnable 中工作 class

Question

我在Java中将这段代码写成Runnable，但我的教授要我添加AtomicInteger，这样就没有线程干扰了。我该怎么做呢？我已经尝试查找如何在代码中使用它的示例，但我不知道在这种情况下该怎么做。

public class GarageWorker {
    public static void main(String[] args) {
        System.out.println("We are going to count the vehicles in the garage");
        System.out.println();
        System.out.println("There are 50 vehicles in the garage to start with!");
        System.out.println();

        GarageWorker garage = new GarageWorker(50);

        Runnable vehicleEnter = garage.new Enter();
        Runnable vehicleExit = garage.new Exit();

        Thread thread1 = new Thread(vehicleEnter);
        Thread thread2 = new Thread(vehicleExit);

        thread1.start();
        thread2.start();
    }

    public GarageWorker(int initialCarCount) {
        counter = initialCarCount;
    }

    public int counter;

    public class Enter implements Runnable {
        public Enter() {

        }

        public int increaseVehicleCount() {
            return ++counter;
        }

        public void run() {
            while (counter < 100) {
                System.out.println("One vehicle entered the garage now there are " + increaseVehicleCount());
            }
        }
    }

    public class Exit implements Runnable {
        public Exit() {

        }

        public int decreaseVehicleCount() {
            return --counter;
        }

        public void run() {
            while (counter > 0) {
                System.out.println("One vehicle left the garage now there are " + decreaseVehicleCount());
            }
        }
    }
}

代码运行良好，但我的教授要我在代码中实现 AtomicInteger class。

Answer 1

我假设您的教授希望您将 counter 更改为 AtomicInteger。首先，您要导入 AtomicInteger 并更改 counter 的声明和构造函数以反映这一点。

import java.util.concurrent.atomic.AtomicInteger;

public GarageWorker(int initialCarCount) {
    counter = new AtomicInteger(initialCarCount);
}

public AtomicInteger counter;

此外，您想更改 increaseVehicleCount 和 decreaseVehicleCount 方法以使用 AtomicInteger 而不是 int。

public int increaseVehicleCount() {
    return counter.incrementAndGet();
}

public int decreaseVehicleCount() {
    return counter.decrementAndGet();
}

incrementAndGet as well as decrementAndGet do just as they say: they increment (or decrement) and subsequently returns the new value. For more information, take a look at the Javadoc.

干杯！

如何让 AtomicInteger 在 Runnable 中工作 class

How to get AtomicInteger to work in a Runnable class

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